ecommerce-escalation v2 test

service.spec.js

import {jest} from '@jest/globals';

import Service, {InsufficientStock} from './service';

describe('checkout', () => {
  test('fails when insufficient stock for desired product', async () => {
    const session = {
      findInventoryByProuctSkus: jest.fn()
        .mockResolvedValueOnce([
          {
            productSku: 'some product sku',
            stock: 2
          }
        ]),
      updateInventoryStock: jest.fn(),
      createOrder: jest.fn()
    };
    const repository = {
      async checkoutTransaction(closure) {
        return closure(session);
      }
    };

    const service = Service(repository);

    await expect(service.checkout([
      {
        productSku: 'some product sku',
        quantity: 10
      }
    ], 'some shipping address', 'some payment details')).rejects.toThrow(InsufficientStock);
    expect(session.findInventoryByProuctSkus).toHaveBeenNthCalledWith(1, ['some product sku']);
    expect(session.updateInventoryStock).not.toHaveBeenCalled();
    expect(session.createOrder).not.toHaveBeenCalled();
  });

  test('creates order when all desired items are in stock', async () => {
    const session = {
      findInventoryByProuctSkus: jest.fn()
        .mockResolvedValueOnce([
          {
            productSku: 'some product sku',
            stock: 30
          }
        ]),
      updateInventoryStock: jest.fn()
        .mockResolvedValueOnce(),
      createOrder: jest.fn()
        .mockResolvedValueOnce('some order id')
    };
    const repository = {
      async checkoutTransaction(closure) {
        return closure(session);
      }
    };

    const service = Service(repository);

    const result = await service.checkout([
      {
        productSku: 'some product sku',
        quantity: 10
      }
    ], 'some shipping address', 'some payment details');

    expect(result).toBe('some order id');
    expect(session.findInventoryByProuctSkus).toHaveBeenNthCalledWith(1, ['some product sku']);
    expect(session.updateInventoryStock).toHaveBeenNthCalledWith(1, [
      {
        productSku: 'some product sku',
        stock: 20
      }
    ]);
    expect(session.createOrder).toHaveBeenNthCalledWith(1, {
      lineItems: [
        {
          productSku: 'some product sku',
          quantity: 10
        },
      ],
      shippingAddress: 'some shipping address',
      paymentDetails: 'some payment details'
    });
  });
});